Reduced dose intravenous acetaminophen

ABSTRACT

Described herein are compositions and methods for intravenous administration of acetaminophen at a single dose level of less than about 1000 mg for the treatment or prevention of pain (e.g., postoperative pain) and/or fever.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to and claims priority to U.S. ProvisionalPatent Application No. 60/987,761, entitled “Reduced Dose IntravenousAcetaminophen” filed on Nov. 13, 2007, which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

In the hospital, particularly in the postoperative setting, pain is aprimary concern of patients. Opioid analgesics have been used to treatpostoperative pain since 1784 and parenteral morphine has been a primarytreatment modality since the 1850s. While opioids are highly effectivein the treatment of many painful conditions, they have side effects anddose-dependent risks including nausea, vomiting, constipation, urinaryretention, sedation, and respiratory depression. Similarly, nonsteroidal anti-inflammatory drugs (NSAIDs), including the older nonselective (dual inhibitor) products and newer cyclo-oxygenase (COX)-2products, have a variety of unwanted side effects especially when usedin the perioperative setting. Non selective NSAIDs are associated withplatelet dysfunction and the potential for bleeding at the surgicalsite, upper gastrointestinal ulcers and bleeding, edema, hypertension,congestive heart failure, renal dysfunction, severe skin reactions suchas Stevens-Johnson syndrome and toxic epidermal necrolysis, anaphylaxis,and most recently, an increased risk of thrombotic cardiovascularevents.

SUMMARY OF THE INVENTION

Described herein are pharmaceutical compositions having a reduced doseof acetaminophen for intravenous administration, and methods of usingthese compositions for treating and/or preventing pain and/or fever in asubject.

In some embodiments, the pharmaceutical compositions described hereincomprise less than about 1 gram of acetaminophen, wherein thepharmaceutical composition is provided as a formulation suitable forintravenous administration. For example, various embodiments maycomprise about 500 mgs to about 1 gram, or about 500 mgs to about 800mgs, or about 500 mgs to about 750 mgs. In various embodiments, thepharmaceutical compositions described herein comprise about 600 mg toabout 700 mg of acetaminophen.

In some embodiments, the pharmaceutical compositions described hereinfurther comprise at least one antioxidant. In some embodiments, the atleast one antioxidant comprises cysteine hydrocloride monohydrate,thiolyglycolic acid, thiolacetic acid, dithiothreitol, reducedglutathione, thiourea, alpha-thioglycerol, cysteine, aceticysteine, ormercaptoethane sulfonic acid, ascorbic acid ascorbic acid derivatives,an organic compound having at least one thiol, an alkyl polyhydroxylatedcompound, or a cycloalkyl polyhydroxylated compound.

In some embodiments, the pharmaceutical composition further comprises abuffering agent (e.g., disodium phosphate dehydrate). In someembodiments, the pharmaceutical composition has a pH from about 4 toabout 8 when in solution. In some embodiments, the pharmaceuticalcomposition has a pH of about 5 to about 6 when in solution.

In some embodiments, the pharmaceutical composition has an osmolalityfrom about 250 mOsm/L to about 400 mOsm/L when in solution. In someembodiments, the pharmaceutical composition further comprises anisotonicity agent. In some embodiments, the isotonicity agent isdextrose, mannitol, or lactose.

In some embodiments, the pharmaceutical composition further comprises atleast one analgesic agent other than acetaminophen. In some embodiments,the at least one analgesic agent other than acetaminophen comprises ananilide, an opioid, an NSAID, a cannabinoid, a pyralazone, or abarbiturate.

In some embodiments, the pharmaceutical composition further comprisesEDTA.

In a further aspect provided herein is a method for preventing orreducing pain or fever in a subject in need thereof, comprisingadministering to the subject, by an intravenous route of administration,a pharmaceutical compositions described herein. In some embodiments, theadministration is repeated at least once with an interval of about 3 toabout 5 hours. In some embodiments, the administration is repeated atleast six times in a period of twenty four hours. In variousembodiments, the administration is repeated three to eight times (e.g.,3 times, 4 times, five times, six times, seven times, or eight times) ina period of twenty four hours and about 3 to about 5 grams ofacetaminophen (e.g., about 3 grams, about 4 grams or about 5 grams) isdelivered over the twenty four hour period. In other embodiments, theadministration is repeated three to eight times in a period of twentyfour hours and less than about 4 grams of acetaminophen is deliveredover the twenty four hour period.

In some embodiments, the pharmaceutical formulation for IVadministration is a solution comprising: about 600 mg to about 700 mg ofacetaminophen, cysteine hydrochloride monohydrate, disodium phosphatedehydrate, and mannitol, wherein the solution has a pH of between about5 and about 6 and an osmolality of between about 200-400 mOsm/L. In someembodiments, the pharmaceutical composition in solution has anacetaminophen concentration of about 0.5% (w/v) to about 10% (w/v). Insome embodiments, the acetaminophen concentration is about 1% (w/v). Insome embodiments, the pharmaceutical composition to be administeredfurther comprises EDTA.

In some embodiments, the subject to be treated is suffering from aninfection. In some embodiments, the subject to be treated is sufferingfrom a fever. In some embodiments, the subject to be treated isunconscious, sedated, fasting, nauseous, or unable to be administered apharmaceutical composition by an oral route.

In some embodiments, the pharmaceutical composition is administered tothe subject after a surgical intervention. In some embodiments, thepharmaceutical composition is administered within three hours of asurgical intervention on the subject. In some embodiments, thepharmaceutical composition is administered within 1 hour of a surgicalintervention on the subject. In some embodiments, the pharmaceuticalcomposition is administered postoperatively. In some embodiments, thesubject to be treated is suffering from postoperative pain.

In various embodiments the pharmaceutical compositions described hereinare administered as a pretreatment.

In another aspect provided herein is a method for preventing or reducingpain or fever in a subject in need thereof, comprising administering tothe subject, by an intravenous route of administration, a pharmaceuticalcomposition described herein.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

DETAILED DESCRIPTION OF THE INVENTION

To date, the standard intravenous (IV) dose of acetaminophen for therelief of pain or fever has been 1000 mg in adults and adolescentsweighing at least 50 kg. At this dose level, the frequency ofacetaminophen administration is limited to a maximum of once every sixhours (i.e., four administrations per twenty four hours) to minimize thepotential for hepatotoxicity. On the other hand, it has generally beennoted that acetaminophen has greatest efficacy during its initial risein plasma concentration, i.e., during the first few hourspost-administration, and is less effective later on after the plasmaconcentration of the drug drops from its peak. While not wishing to bebound by theory, it is thought that this change in efficacy is likelydue to a time and concentration-dependent modulation of the central andperipheral nociceptive pathways through which acetaminophen acts.

Further, if the duration of effect of a 1000 mg dose of acetaminophen isshorter in duration than 6 hours, the use of this dose is limited sincedosing more frequently than every 6 hours, e.g., every 4 hours, leaves agap in coverage due to the 4 g acetaminophen maximum daily limit. In thetreatment of fever, a dose less than 1000 mg may be fully effective dueto the fact that a lower plasma level (compared to that needed for pain)is needed to effectively reduce fever.

Thus, intravenous administration of a reduced dose of acetaminophen, asdescribed herein, permits more frequent IV acetaminophen administrationto yield better overall relief of symptoms for many patients whileavoiding any potential gap artificially created by the daily limit.

Also, the reduced acetaminophen IV dose affords greater flexibility tothe physician in customizing treatments to the needs of the patient,selecting the dose of other drugs for use in combination therapies andallowing for smoother transitions to oral products containingacetaminophen.

Accordingly, described herein are reduced IV dose formulations ofacetaminophen for intravenous administration and the use of reduced IVdoses of acetaminophen for use for the treatment or prevention of painand/or fever.

Certain Terminology

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart to which the claimed subject matter belongs. In the event that thereis a plurality of definitions for terms herein, those in this sectionprevail. Where reference is made to a URL or other such identifier oraddress, it is understood that such identifiers can change andparticular information on the internet can come and go, but equivalentinformation can be found by searching the internet or other appropriatereference source. Reference thereto evidences the availability andpublic dissemination of such information.

It is to be understood that the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of any subject matter claimed. In this application,the use of the singular includes the plural unless specifically statedotherwise. It must be noted that, as used in the specification and theappended claims, the singular forms “a”, “an” and “the” include pluralreferents unless the context clearly dictates otherwise. It should alsobe noted that use of “or” means “and/or” unless stated otherwise.Furthermore, use of the term “including” as well as other forms, such as“include”, “includes”, and “included” is not limiting.

Definition of standard chemistry terms may be found in reference works,including Carey and Sundberg “ADVANCED ORGANIC CHEMISTRY 4^(TH) ED.”Vols. A (2000) and B (2001), Plenum Press, New York. Unless otherwiseindicated, conventional methods of mass spectroscopy, NMR, HPLC, IR andUV/Vis spectroscopy and pharmacology, within the skill of the art areemployed. Unless specific definitions are provided, the nomenclatureemployed in connection with, and the laboratory procedures andtechniques of, analytical chemistry, synthetic organic chemistry, andmedicinal and pharmaceutical chemistry described herein are those knownin the art. Standard techniques can be used for chemical syntheses,chemical analyses, pharmaceutical preparation, formulation, anddelivery, and treatment of patients. Reactions and purificationtechniques can be performed e.g., using kits of manufacturer'sspecifications or as commonly accomplished in the art or as describedherein. The foregoing techniques and procedures can be generallyperformed of conventional methods well known in the art and as describedin various general and more specific references that are cited anddiscussed throughout the present specification. Throughout thespecification, groups and substituents thereof can be chosen by oneskilled in the field to provide stable moieties and compounds.

The terms “treat,” “treating” or “treatment,” and other grammaticalequivalents as used herein, include alleviating, abating or amelioratinga disease or condition symptoms, preventing additional symptoms,ameliorating or preventing the underlying metabolic causes of symptoms,inhibiting the disease or condition, e.g., arresting the development ofthe disease or condition, relieving the disease or condition, causingregression of the disease or condition, relieving a condition caused bythe disease or condition, or stopping the symptoms of the disease orcondition, and are intended to include prophylaxis. The terms furtherinclude achieving a therapeutic benefit and/or a prophylactic benefit.By therapeutic benefit is meant eradication or amelioration of theunderlying disorder being treated. Also, a therapeutic benefit isachieved with the eradication or amelioration of one or more of thephysiological symptoms associated with the underlying disorder such thatan improvement is observed in the patient, notwithstanding that thepatient may still be afflicted with the underlying disorder. Forprophylactic benefit, the compositions may be administered to a patientat risk of developing a particular disease, or to a patient reportingone or more.

The terms “effective amount,” “therapeutically effective amount” or“pharmaceutically effective amount” as used herein, refer to asufficient amount of at least one agent or compound being administeredwhich will relieve to some extent one or more of the symptoms of thedisease or condition being treated. The result can be reduction and/oralleviation of the signs, symptoms, or causes of a disease, or any otherdesired alteration of a biological system. For example, an “effectiveamount” for therapeutic uses is the amount of the composition comprisingthe compound as disclosed herein required to provide a clinicallysignificant decrease in pain. An additional example is that an“effective amount” may be a dosage that decreases a fever. Anappropriate “effective” amount in any individual case may be determinedusing techniques, such as a dose escalation study.

The terms “administer,” “administering,” “administration,” and the like,as used herein, refer to the methods that may be used to enable deliveryof compounds or compositions to the desired site of biological action.These methods include, but are not limited to oral routes, intraduodenalroutes, parenteral injection (including intravenous, subcutaneous,intraperitoneal, intramuscular, intravascular or infusion), topical andrectal administration. Those of skill in the art are familiar withadministration techniques that can be employed with the compounds andmethods described herein, e.g., as discussed in Goodman and Gilman, ThePharmacological Basis of Therapeutics, current ed.; Pergamon; andRemington's, Pharmaceutical Sciences (current edition), Mack PublishingCo., Easton, Pa. In preferred embodiments, the compositions comprisingacetaminophen as described herein are administered intravenously.

The term “acceptable” as used herein, with respect to a formulation,composition or ingredient, means having no persistent detrimental effecton the general health of the subject being treated.

The term “antioxidant” refers to a compound that prevents oxygen oroxygen-derived free radicals from interacting with other substances.Antioxidants are added to minimize or retard oxidative processes thatoccur with some drugs or excipients upon exposure to oxygen or in thepresence of free radicals. These processes can often be catalyzed bylight, temperature, hydrogen on concentration, presence of trace metalsor peroxides.

The terms “enhance” or “enhancing,” as used herein, means to increase orprolong either in potency or duration a desired effect. Thus, in regardto enhancing the effect of therapeutic agents, the term “enhancing”refers to the ability to increase or prolong, either in potency orduration, the effect of other therapeutic agents on a system. An“enhancing-effective amount,” as used herein, refers to an amountadequate to enhance the effect of another therapeutic agent in a desiredsystem.

“Concurrent administration,” “administered in combination” or similarphrases referring to the acetaminophen and at least one additionalcomponent means that the components are administered concurrently to themammal being treated. By “concurrently,” it is meant that each componentmay be administered at the same time or sequentially in any order atdifferent points in time. However, if not administered at the same time,they should be administered sufficiently closely in time so as toprovide the desired enhancement of treatment effect. Suitable dosingintervals and the order of administration with such compounds will bereadily apparent to those skilled in the art, once armed with thepresent disclosure. Preferably both components are administered at thesame time or within the same hour.

As used herein, the term “animal” shall refer to a vertebrate animal.More preferably, the vertebrate animal is a mammal. As used herein, theterm “mammal” shall refer to the Mammalia class of higher vertebrates.The term “mammal” includes, but is not limited to, a human.

As used herein, the term “pain” shall refer to all types of pain,including, but not limited, to nociceptive pain, neuropathic pain,post-operative pain, lower back pain, cluster headaches, herpesneuralgia, phantom limb pain, central pain, dental pain,opioid-resistant pain, visceral pain, surgical pain, bone injury pain,pain during labor and delivery, pain resulting from burns, includingsunburn, post partum pain, migraine, and genitourinary tract-relatedpain including cystitis. Levels of pain in a subject can be quantifiedusing standard subjective assay scales of pain including, e.g., the PainIntensity Visual Analogue Scale or Pain Intensity Categorical Scale.Likewise, levels of “pain relief” can also be quantified by a subjectiveassay, e.g., Time to Perceptible and Meaningful Pain Relief.

The terms “intravenous formulation,” or “intravenous acetaminophenformulation” shall refer to a single dose formulation of acetaminophenthat is provided as a lyophilized powder (or other solid form) that,once reconstituted in solution, is physiologically compatible withintravenous administration (e.g., by injection, infusion or otherwise).Alternatively, the terms refer to a formulation that is provided as asolution.

Reduced Dose Acetaminophen Formulations for Intravenous Administration(IV Formulations)

In some embodiments, the IV acetaminophen formulations described hereinare in the form of a lyophilized powder to be reconstituted in solutionunder sterile conditions prior to administration. In other embodiments,the IV acetaminophen formulations are provided as sterile solutionsready for administration. Appropriate containers (e.g., vials, bottles,ampules, containers, etc.) for the IV formulations in either of theforms just described, as well as aseptic techniques are well known.

IV Acetaminophen Dosage

In various embodiments, the single dose IV acetaminophen formulationcontains less than about 1 gram of acetaminophen. In some embodiments,the single dose IV acetaminophen contains about 500 to about 1000 mgs.In some embodiments, the single dose IV acetaminophen contains about 550mgs to about 900 mgs. In some embodiments, the single dose IVacetaminophen formulations described herein contain about 550 mg toabout 800 mg of acetaminophen, i.e., about 560 mg, 570 mg, 580 mg, 600mg, 610 mg, 620 mg, 630 mg, 640 mg, 650 mg, 660 mg, 670 mg, 675 mg, 680mg, 690 mg, 700 mg, 720 mg, 750 mg, 775 mg, or any other amount ofacetaminophen from about 550 mg to about 800 mg of acetaminophen. Insome embodiments, an IV acetaminophen formulation contains about 600 mgto about 700 mg of acetaminophen, i.e., about 610 mg, 620 mg, 630 mg,640 mg, 650 mg, 660 mg, 670 mg, 680 mg, 690 mg, or any other amount ofacetaminophen from about 600 mg to about 700 mg of acetaminophen. In oneembodiment, the acetaminophen formulation contains about 650 mg ofacetaminophen.

In some embodiments, the concentration of acetaminophen in an IVformulation solution described herein is about 0.3% (w/v) to about 12%(w/v), i.e., about 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%,1.5%, 2.5%, 3%, 3.7%, 4%, 4.5%, 5%, 6%, 7%, 8%, 8.5%, 9%, 10%, 10.5%,11%, or any other concentration from about 0.3% (w/v) to about 12%(w/v). In some embodiments the concentration of acetaminophen is about0.7% (w/v) to about 1.4% (w/v), i.e., about 0.8%, 0.9%, 1.0%, 1.1%,1.2%, 1.3% or any other concentration of acetaminophen from about 0.7%(w/v) to about 1.4% (w/v). In one embodiment, the concentration ofacetaminophen is about 1.0% (w/v).

In some embodiments, the volume of an IV acetaminophen formulationsolution is about 30 to about 200 ml, i.e., about 30, 35, 40, 45, 55,60, 65, 75, 80, 85, 90, 92, 95, 100, 105, 110, 125, 130, 150, 175, 180,or another volume of IV formulation solution from about 30 to about 200ml. In some embodiments, the volume of the IV formulation is about 75 toabout 125 ml. In another embodiment the volume is about 40 to about 75ml. In one embodiment, the volume of the IV formulation is about 100 ml.

Antioxidants

Generally, the acetaminophen formulations described herein also containsat least one antioxidant to increase the stability of acetaminophen insolution. Examples of suitable antioxidants include, but are not limitedto, cysteine hydrocloride monohydrate, thiolyglycolic acid, thiolaceticacid, dithiothreitol, reduced glutathione, thiourea, alpha-thioglycerol,cysteine, aceticysteine, methionine, mercaptoethane sulfonic acid,metabisulfite, ascorbic acid ascorbic acid derivatives (e.g., ascorbylpalmitate), sodium citrate, an organic compound having at least onethiol, an alkyl polyhydroxylated compound, a cycloalkyl polyhydroxylatedcompound, a hydroxypolycarboxylic acid, an alpha-hydroxypolycarboxylicacid (e.g., citric acid), tocotrienol, dimethyl glycine, betaine,butylated hydroxyanisole, butylated hydroxytoluene, tocopherol,tocopherol polyethylene glycol succinate, butylated hydroxytoluene(BHT), butylated hydroxyanisole (BHA), propyl gallate, hydroquinone,hydroxycoumarins, ethanolamine, lecithin, cephalin, malic acid,sorbitol, phosphoric acid, thiodipropionic acid and its esters,dithiocarbamates or any combination thereof. In one embodiment, theacetaminophen formulation is free of polyethylene glycol or a derivativethereof. In another embodiment, the acetaminophen formulation is free ofsulfites. In one embodiment, the antioxidant is cysteine hydrocloridemonohydrate. In yet another embodiment, the antioxidant is mannitol.

In some embodiments, the amount % (w/w) of the antioxidant in the solidform of the IV formulation (i.e., prior to preparation in solution) isabout 0.10% (w/w) to about 5.0% (w/w), i.e., 0.15% (w/w), 0.17% (w/w),0.20% (w/w), 0.30% (w/w), 0.40% (w/w), 0.45% (w/w), 0.50% (w/w), 0.52%(w/w), 0.55% (w/w), 0.60% (w/w), 0.70% (w/w), 0.80% (w/w), 1.0% (w/w),1.3% (w/w), 1.5% (w/w), 1.7% (w/w), 2.0% (w/w), 2.2% (w/w), 2.3% (w/w),2.5% (w/w), 2.7%, 2.8%, 3.0% (w/w), 3.2%, 3.5% (w/w), 3.6% (w/w), 4.0%(w/w), 4.7% (w/w), or any other amount of antioxidant % (w/w) from about0.10% (w/w) to about 5.0% (w/w). In some embodiments, the amount % (w/w)of antioxidant is about 0.30% (w/w) to about 1.0% (w/w). In oneembodiment, the amount % (w/w) of antioxidant is about 0.50% (w/w).

In some embodiments, the concentration of the antioxidant in an IVformulation solution prior to administration ranges from about 0.01mg/ml to about 10 mg/ml, i.e., 0.02 mg/ml, 0.03 mg/ml, 0.05 mg/ml, 0.08mg/ml, 0.09 mg/ml, 0.10 mg/ml, 0.12 mg/ml, 0.13 mg/ml, 0.15 mg/ml, 0.18mg/ml, 0.20 mg/ml, 0.22 mg/ml, 0.25 mg/ml, 0.27 mg/ml, 0.30 mg/ml, 0.40mg/ml, 0.45 mg/ml, 0.50 mg/ml, 0.60 mg/ml, 0.80 mg/ml, 1.2 mg/ml, 1.5mg/ml, 2.0 mg/ml, 2.5 mg/ml, 3.0 mg/ml, 3.5 mg/ml, 4.0 mg/ml, 5.0 mg/ml,6.0, mg/ml 7.5 mg/ml, 8.0 mg/ml, 9 mg/ml, 9.5 mg/ml, or any otherconcentration of antioxidant from about 0.01 mg/ml to about 10 mg/ml. Insome embodiments, the concentration of antioxidant is about 0.08 mg/mlto about 0.50 mg/ml. In one embodiment, the concentration of antioxidantis about 0.25 mg/ml.

Buffering Agents

In some embodiments, an IV acetaminophen formulation contains at leastone buffering agent to maintain the pH of the formulation within anacceptable range as described herein. The buffer used is a buffercompatible with parenteral administration in humans, the pH of which maybe adjusted between 4 and 8. In some embodiments, the pH of an IVacetaminophen formulation is from about pH 4 to about pH 8, i.e., pH4.5, pH 4.6, pH 4.8, pH 5.0, pH 5.5, pH 6.2, pH 6.5, pH 7.5, or anyother pH value from about pH 4 to about pH 8. In some embodiments, thepH of the IV acetaminophen formulation is from about pH 5 to about pH7.0, i.e., about pH 5.2, pH 5.5, pH 5.6, pH 6.0, pH, 6.4, or any otherpH value from about pH 5 to about pH 7.0. In one embodiment, the IVacetaminophen formulation has a pH of about 5 to about 6.

In some embodiments, buffering agents have a pKa from about 4.5 to about6.5, i.e., 4.6, 4.8, 5.0, 5.2, 5.3, 5.4, 5.5, 5.8, 6.0, 6.2, 6.4, or anyother pKa from about 4.5 to about 6.5.

In some embodiments, the buffering agent is a pharmaceuticallyacceptable salt or acid of citrate, phosphate, acetate, glutamate,tartrate, benzoate, lactate, histidine or other amino acids, gluconate,malate, succinate, formate, propionate, carbonate, or any combinationthereof adjusted to an appropriate pH, as described herein, with acid(e.g., hydrochloric acid) or base (e.g., sodium hydroxide) as required.In one embodiment, the buffering agent is disodium phosphate dehydrate.

In some embodiments, the amount % (w/w) of the buffering agent in thesolid form of the IV formulation (i.e., prior to preparation insolution) is about 0.05% (w/w) to about 2% (w/w), i.e., about 0.08%(w/w), 0.10% (w/w), 0.15% (w/w), 1.0% (w/w), 1.3% (w/w), 1.5% (w/w),1.7% (w/w), 0.20% (w/w), 0.22% (w/w), 0.25% (w/w), 0.26% (w/w), 0.27%(w/w), 0.28% (w/w), 0.30% (w/w), 0.35% (w/w), 0.40% (w/w), 0.50% (w/w),0.60% (w/w), 0.70% (w/w), 0.80% (w/w), 1.2% (w/w), 1.4% (w/w), 1.5%(w/w), 1.7%, or any other amount of buffering agent % (w/w) from about0.05% (w/w) to about 2.0% (w/w). In some embodiments, the amount % (w/w)of the buffering agent is about 0.10% to about 0.70%. In one embodiment,the amount % (w/w) of the buffering agent is about 0.26%.

In some embodiments, the concentration of the buffering agent in an IVformulation solution prior to administration ranges from about 0.01mg/ml to about 10 mg/ml, i.e., 0.02 mg/ml, 0.03 mg/ml, 0.05 mg/ml, 0.08mg/ml, 0.09 mg/ml, 0.10 mg/ml, 0.12 mg/ml, 0.13 mg/ml, 0.15 mg/ml, 0.30mg/ml, 0.5 mg/ml, 0.8 mg/ml, 1.2 mg/ml, 1.5 mg/ml, 2.0 mg/ml, 2.5 mg/ml,3.0 mg/ml, 3.5 mg/ml, 4.0 mg/ml, 5.0 mg/ml, 6.0, mg/ml 7.5 mg/ml, 8.0mg/ml, 9 mg/ml, 9.5 mg/ml, or any other concentration of buffering agentfrom about 0.01 mg/ml to about 10 mg/ml. In some embodiments, theconcentration of buffering agent is about 0.08 mg/ml to about 0.30mg/ml. In one embodiment, the concentration of buffering agent is about0.13 mg/ml.

Isotonicity Agents

In some embodiments, an IV acetaminophen formulation also contains oneor more isotonicity agents to maintain the osmolality of the formulationin a range that is physiologically compatible with IV administration. Insome embodiments, the osmolality of the IV acetaminophen formulation isabout 230 mOsm/L to about 420 mOsm/L, i.e., about 240 mOsm/L, 250mOsm/L, 260 mOsm/L, 270 mOsm/L, 280 mOsm/L, 290 mOsm/L, 300 mOsm/L, 305mOsm/L, 310 mOsm/L, 320 mOsm/L, 350 mOsm/L, 375 mOsm/L, 400 mOsm/L orany other osmolality from about 240 mOsm/L to about 420 mOsm/L. In someembodiments, the osmolality of the IV acetaminophen formulation is about280 mOsm/L to about 320 mOsm/L, i.e., about 290 mOsm/L, 295 mOsm/L, 300mOsm/L, 305 mOsm/L, 310 mOsm/L, 315 mOsm/L, or any other osmolality fromabout 280 mOsm/L to about 320 mOsm/L. In one embodiment, the osmolalityof the IV acetaminophen formulation is about 200-400 mOsm/L.

Suitable agents for adjusting the isotonicity of IV acetaminophenformulations include, but are not limited to, mannitol, sorbitol,glycerol, sucrose, glucose, dextrose, levulose, fructose, lactose,polyethylene glycols 400 to 4000, phosphates, sodium chloride, potassiumchloride, calcium chloride, calcium gluconoglucoheptonate, dimethylsulfone. In one embodiment, the isotonicity agent is mannitol.

In some embodiments, the amount % (w/w) of the isotonicity agent in thesolid form of the IV formulation (i.e., prior to preparation insolution) is about 5% (w/w) to about 95% (w/w), i.e., about 10% (w/w),15% (w/w), 20% (w/w), 25% (w/w), 30% (w/w), 35% (w/w), 40% (w/w), 45%(w/w), 50% (w/w), 55% (w/w), 60% (w/w), 65% (w/w),70% (w/w), 72% (w/w),74% (w/w), 76% (w/w), 78% (w/w), 79% (w/w), 80% (w/w), 81% (w/w), 82%(w/w), 84% (w/w), 86% (w/w), 90% (w/w), 92% (w/w), or any other amountof isotonicity agent % (w/w) from about 5% (w/w) to about 95% (w/w). Insome embodiments, the amount of isotonicity agent % (w/w) is about 65%(w/w) to about 85% (w/w). In one embodiment, the amount of isotonicityagent % (w/w) is about 79%.

In some embodiments, the concentration of the isotonicity agent in an IVformulation solution prior to administration ranges from about 1.0 mg/mlto about 150 mg/ml, i.e., 1.0 mg/ml, 2.0 mg/ml, 3.0 mg/ml, 3.5 mg/ml,4.0 mg/ml, 4.5 mg/ml, 5.0 mg/ml, 8.0 mg/ml, 12 mg/ml, 15 mg/ml, 20mg/ml, 25 mg/ml, 30 mg/ml, 32 mg/ml, 35 mg/ml, 37 mg/ml, 38 mg/ml, 40mg/ml, 50 mg/ml, 60, mg/ml, 75 mg/ml, 80 mg/ml, 90 mg/ml, 95 mg/ml, 100,110, 120, 140, or any other concentration of buffering agent from about5 mg/ml to about 150 mg/ml. In some embodiments, the concentration ofbuffering agent is about 0.08 mg/ml to about 0.30 mg/ml. In oneembodiment, the concentration of buffering agent is about 0.13 mg/ml.

Stabilizers

In some embodiments, IV acetaminophen formulations described herein alsoinclude a stabilizer, e.g., a chelating agent such as ethylene diaminotetraacetic acid (EDTA), ethylene diamino,N,N′-diacetic-N,N′-dipropionic acid, ethylene diamino tetraphosphonicacid, 2,2′-(ethylene diamino) dibutyric acid, nitrilotriacetic, acid, orethylene-glycol bis(diaminoethyl ether) N,N,N′,N′-tetraacetic acid andsodium or calcium salts thereof. In some embodiments, the IVacetaminophen formulation includes EDTA as the stabilizer.

In some embodiments, the IV acetaminophen formulations described hereincontain a stabilizer in the amount of about 0.005 to about 1.0 mg/ml. Insome embodiments, the stabilizer is present in an amount of about 0.01mg/ml, 0.05 mg/ml, 0.1 mg.ml, 0.5 mg/ml, or 1.0 mg/ml.

In some embodiments, to reduce oxidation of acetaminophen in solutionand thereby increase its stability, oxygen is removed from an IVformulation solution by bubbling an inert gas (e.g., argon or nitrogen)through the solution under sterile conditions. Methods for minimizingoxidative degradation of acetamininophen solutions during storage aredescribed in further detail in, e.g., U.S. Pat. No. 6,992,218, which isincorporated herein by reference in its entirety.

Methods of Treatment

In many cases, IV administration of acetaminophen is considered the mostsuitable route of administration for expedient and efficacious relief ofa patient's pain or fever, particularly in a hospital setting. In someembodiments, a subject to be administered an IV formulation ofacetaminophen (e.g., an adult subject or adolescent weighing at leastabout 50 kg), as described herein, is unconscious, sedated, fasting,nauseous, or unable to be administered a pharmaceutical composition byan oral route. Additionally, the rectal route is associated with highlyvariable bioavailability and slow absorption, and in children, theefficacious rectal dose exposes some pediatric patients to a potentiallytoxic exposure. In some embodiments, a patient suffering from pain orfever is in need of a faster onset of pain relief or fever treatmentthan possible by acetaminophen administration through an administrationroute other than by an IV administration.

In some embodiments, the IV formulations described herein are used as apretreatment to another therapy. In some of these embodiments,pretreatment with an IV formulation described herein allows the use of alower dose of acetaminophen. In some embodiments, the IV formulationdescribed herein is administered before chemotherapy treatment,radiation treatment, a biopsy, or a blood transfusion. It should beunderstood that these are non-limiting examples and that the IVformulations described herein can be administered as a pretreatment toany therapy where pain and/or fever are predicted to occur.

The IV formulations described herein can be used for reducing painconditions including, but not limited to, acute nociceptive pain, acuteneuropathic pain, postoperative pain, lower back pain, clusterheadaches, herpes neuralgia, phantom limb pain, central pain, dentalpain, opioid-resistant pain, visceral pain, surgical pain, proceduralpain, bone injury pain, pain during labor and delivery, pain resultingfrom burns, post partum pain, headache, muscular aches, backache,arthritis pain, the common cold, toothache, dental pain, osteoarthritispain, menstrual pain, menstrual cramps, migraine, and genitourinarytract-related pain including cystitis. In some embodiments, the IVformulation is administered preemptively to a subject, i.e., prior tothe onset of pain or a pain-inducing condition or stimulus (e.g., asurgical operation). In some embodiments, the IV formulations describedherein are used to reduce fever, including, but not limited to, feverdue to infections, drug reactions, allergic reactions, transfusionreactions, stroke, surgery, heat stroke, rheumatic diseases, cancer, orfever of unknown origin. In some embodiments, the IV formulationsdescribed herein are administered to a patient undergoing a dentalprocedure.

In some embodiments, the IV formulation is administered to a subjectafter undergoing a surgical intervention, e.g., within about 12 hoursafter a surgical intervention, i.e., within 11 hours, 10 hours, 9 hours,8 hours, 6 hours, 5 hours, 4 hours, 3 hours, 2 hours, 1 hours, 45minutes, 30 minutes 15 minutes, 5 minutes, or any period within about 12hours following a surgical intervention.

In some embodiments, a subject is administered the IV formulation priorto a surgical intervention, e.g., about 4 hours or less prior to thesurgical intervention, i.e., about 3 hours, 2 hours, 1 hours, 30minutes, 15 minutes or even during the surgical intervention itself

Depending on the concentration of acetaminophen in an IV formulationsolution and consistent with the acetaminophen dose levels describedherein, the volume of IV formulation solution to be administered canvary from about 1 mL to about 200 mL, e.g., 5 mL, 10 mL, 20 mL, 25 mL,30 mL, 40 mL, 50 mL, 60 mL, 65 mL, 70 mL, 85 mL, 90 mL, 100 mL, 110 mL,120 mL, 130 mL, 140 mL, 150 mL, 160 mL, 180 mL, or any other volume ofIV formulation solution from about 1 mL to about 200 mL.

In some embodiments, the amount of time required for administration ofthe IV formulation ranges from about 1 minute to about 1 hours, i.e.,about 5 minutes, 10 minutes, 11 minutes, 15 minutes, 20 minutes, 30minutes, 45 minutes, or any other administration time from about 1minute to about 1 hour. In some embodiments, the amount of time requiredfor administration of the IV formulation ranges from about 5 minutes toabout 45 minutes, or about 5 minutes to about 30 minutes, or about 5minutes to about 15 minutes.

Depending on the severity and persistence of a subject's condition, andin accordance with a medical caregiver's judgment, an IV formulationdose of acetaminophen, as described herein, can be administered in aninterval to allow for the administration of about 3 to about 5 grams ina 24 hour period. In some embodiments, the IV formulation ofacetaminophen is administered in an interval sufficient to allow for theadministration of about 4 grams in a 24 hour period. In someembodiments, the IV formulation is administered between 1 to 6 times,i.e., 1, 2, 3, 4, 5, 6 times every twenty four hours, as deemednecessary by a medical caregiver. In some embodiments, the frequency ofadministration is not greater than once every four hours.

In various embodiments, the IV formulation of acetaminophen is dosed soas to provide less than about 4 grams over a 24 hour period. In variousembodiments, the IV formulation of acetaminophen is dosed three to sixtimes in a 24 hour period. For example, in some embodiments, the IVformulation of acetaminophen is dosed three times in a 24 hour period.In other embodiments, the IV formulation of acetaminophen is dosed fourtimes in a 24 hour period. In still other embodiments, the IVformulation of acetaminophen is dosed five times in a 24 hour period. Insome embodiments, the IV formulation of acetaminophen is dosed six timesin a 24 hour period. In some embodiments, the IV formulation ofacetaminophen is dosed seven times in a 24 hour period. In someembodiments, the IV formulation of acetaminophen is dosed eight times ina 24 hour period.

Combination Therapies

The acetaminophen IV formulations described herein can also be used incombination with other therapeutic reagents, e.g., other analgesics,antipyretics, or anti-inflammatory agents that are selected for theirtherapeutic or palliative value. In general, where a combination therapyis employed, other agents do not have to be administered in the samepharmaceutical composition as acetaminophen, and may, because ofdifferent physical and chemical characteristics, be administered bydifferent routes. The determination of the mode of administration andthe advisability of administration, where possible, in the samepharmaceutical composition, is well within the knowledge of the skilledclinician with the teachings described herein. The initialadministration of either the IV acetaminophen formulation or the one ormore therapeutic agents (e.g., analgesic agents other thanacetaminophen) to be used in combination with acetaminophen can be madeaccording to established protocols known in the art, and then, basedupon the observed effects, the dosage, modes of administration and timesof administration can be modified by the skilled clinician.

The particular choice of compounds (e.g., analgesic agents) for use incombination with the IV acetaminophen formulation described herein willdepend on the diagnosis of the attending physicians (or other medicalcaregivers) and their judgment of the condition of the patient and theappropriate treatment protocol. The compounds may be administeredconcurrently (e.g., simultaneously, essentially simultaneously or withinthe same treatment protocol) or sequentially, depending upon theseverity of pain experienced by the patient, the nature of the disease,disorder, or condition, the condition, and the actual choice ofcompounds used. The determination of the order of administration, andthe number of repetitions of administration of each therapeutic agentduring a treatment protocol, is well within the knowledge of the skilledphysician after evaluation of the disease being treated and thecondition of the patient.

For combination therapies described herein, dosages of the compounds tobe co-administered with an acetaminophen IV formulation will varydepending on the type of co-drug employed, on the amount of painexperienced by the patient, the risk for addiction, the disease orcondition being treated and so forth. In addition, when co-administeredwith one or more biologically active agents, the acetaminophen IVformulation provided herein may be administered either simultaneouslywith the biologically active agent(s), or sequentially. If administeredsequentially, the attending physician will decide on the appropriatesequence of administering protein in combination with the biologicallyactive agent(s).

In any case, the multiple therapeutic agents (one of which is anacetaminophen IV formulation described herein) may be administered inany order or even simultaneously. If simultaneously, the multipletherapeutic agents may be provided in a single, unified IV form, or inmultiple forms (by way of example only, either as a single IVformulation, as multiple IV formulations, or as IV formulation and apill). One of the therapeutic agents may be given in multiple doses, orboth may be given as multiple doses. If not simultaneous, the timingbetween the multiple doses may vary from more than 1 minute to less than12 hours. In some embodiments, the timing between the multiple doses isfrom between about 1 minute to about 6 hours, or about 1 minute andabout 3 hours, or about 1 minute and about 1 hour. In addition, thecombination methods, compositions and formulations are not to be limitedto the use of only two agents; the use of multiple therapeuticcombinations is also envisioned.

The pharmaceutical agents which make up the combination therapydisclosed herein may be a combined dosage form (i.e., a combined IVformulation) or in separate dosage forms intended for substantiallysimultaneous administration. The pharmaceutical agents that make up thecombination therapy may also be administered sequentially, with eithertherapeutic compound being administered by a regimen calling fortwo-step administration. The two-step administration regimen may callfor sequential administration of the active agents or spaced-apartadministration of the separate active agents. The time period betweenthe multiple administration steps may range from, a few minutes toseveral hours, depending upon the properties of each pharmaceuticalagent, such as potency, solubility, bioavailability, plasma half-lifeand kinetic profile of the pharmaceutical agent.

The compounds described herein and combination therapies can beadministered before, during or after the occurrence of a fever orpainful condition, and the timing of administering the compositioncontaining a compound can vary. Thus, for example, the compounds can beused as a prophylactic and can be administered continuously to subjectswith a propensity to develop conditions (e.g., body aches and chillsfollowing chemotherapy treatment) or diseases in order to prevent theoccurrence of the disease or condition. The compounds and compositionscan be administered to a subject during or as soon as possible after theonset of the symptoms. The administration of the compounds can beinitiated within the first 48 hours of the onset of the symptoms,preferably within the first 48 hours of the onset of the symptoms, morepreferably within the first 6 hours of the onset of the symptoms, andmost preferably within 3 hours of the onset of the symptoms.

A compound is preferably administered as soon as is practicable beforeor after the onset of a painful condition (e.g., postoperative pain),and for a length of time necessary for the treatment of the disease,such as, for example, from about 1 month to about 3 months.

Exemplary Analgesic Agents for Use in Combination with an AcetaminophenIV Formulation

Opioids

In some embodiments, an acetaminophen IV formulation described herein isused in any combination with one or more opioids, which include, but arenot limited to allylprodine, alphamethylfentanyl, alfentanil,bezitramide, buprenorphine, butorphanol, carfentanyl, codeine,dextropropoxyphene, dextromoramide, dezocine, diacetylmorphine,dihydrocodeine, dipapanone, dismorphine, dihydrocodeine, etorphine,fentanyl, hydrocodone, hydromorphone, ketobemidone, lefetamine,levorphanol, levo-alphacetylmethadol, levomethorphan, meptazinol,methadone, morphine, nalbuphine, nicomorphine, ohmefentanyl, opium,oripavine, oxycodone, oxymorphone, methadone, PEPAP, pentazocine,pethidine, phenazocine, piritamide, prodine, propoxyphene napsylate,remifentanil, sufentanil, tilidine, thebaine, tramadol, and tapentadol.

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

In some embodiments, an acetaminophen IV formulation described herein isused in any combination with one or more NSAIDs, which include, but arenot limited to amoxiprin, benorilate, choline magnesium salicylate,diflusinal, faislamine, methyl salicylate, magnesium salicylate, salicylsalicylate, diclofenac, aceclofenac, acemetacin, bromfenac, ethenzamide,etodolac, indometacin, nabumetone, sulindac, tolmetin, carprofen,fenbufen, fenoprofen, flurbiprofen, ketoprofen, ketorolac, loxoprofen,naproxen, oxaprozin, tiaprofenic acid, suprofen, mefenamic acid,meclofenamic acid, phenylbutazone, metamizole, oxyphenbutazone,sulfinpyrazone, piroxicam, lornoxicam, meloxicam, tenoxicam, nimesulidesalixylates, arylalkanoic acids, 2-arylpropionic acids (profens),n-arylanthranilic acids (fenamic acids), pyrazolidine derivatives,oxicams, and COX-2 inhibitors.

Other Analgesic Agents

In some embodiments, an acetaminophen iv formulation described herein isused in any combination with one or more analgesic agents not describedabove, including, but not limited to, barbiturates (e.g., butalbital),pyrazolones (e.g., aminophenazone, metamizole, phenazone), cannabinoids(e.g., tetrahydrocannabinol), ziconotide, choline magnesium fentanyl,oxycodone, codeine, dihydrocodeine, dihydrocodeinone enol acetate,morphine, desomorphine, apomorphine, diamorphine, pethidine, methadone,dextropropoxyphene, pentazocine, dextromoramide, oxymorphone,hydromorphone, dihydromorphine, noscapine, papverine, papveretum,alfentanil, buprenorphine, tramadol and pharmaceutically acceptablesalts, derivatives, homologs or analogs thereof as well as opioidagonists.

Exemplary Antiemetic Agents for Use in Combination with an AcetaminophenIV Formulation

In some embodiments, an acetaminophen iv formulation described herein isused in any combination with one or more antiemetic agents not describedabove, including, but not limited to, antihistamines (e.g., Cyclizine,Diphenhydramine, Dimenhydrinate, Meclizine, Promethazine, Pentazine,Phenergan, Promacot, or Hydroxyzine); 5-HT₃ receptor antagonists (e.g.,Dolasetron, Granisetron, Ondansetron, Tropisetron, or Palonosetron); anddopamine antagonists (e.g., Domperidone, Droperidol, haloperidol,chlorpromazine, promethazine, prochlorperazine, or metoclopramide).

Kits

In some embodiments provided herein are kits that can simplify theadministration of an IV acetaminophen formulation to a patient. In someembodiments, a kit comprises a unit dosage form of an acetaminophen IVformulation as described herein provided as a sterile lyophilate to bereconstituted by addition of sterile water. In other embodiments, the IVformulation is provided as a sterile degassed solution ready foradministration. The kit can further comprise a label or printedinstructions on the use of the acetaminophen IV formulation to treatpain or fever. The kit can also further comprise a unit dosage form ofanother therapeutic agent, for example, a container containing aneffective amount of a second analgesic agent for use in combination withthe acetaminophen IV formulation. In some embodiments, a kit furthercomprises a device that is useful for administering the IV formulationunit dosage forms. Examples of such a device include, but are notlimited to, a syringe or a drip bag.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be understood that such embodiments areprovided by way of example only. Numerous variations, changes, andsubstitutions can be made without departing from the scope of theinvention. It should be understood that various alternatives to theembodiments of the invention described herein may be employed inpracticing the invention. It is intended that the following claimsdefine the scope of the invention and that methods and structures withinthe scope of these claims and their equivalents be covered thereby.Thus, these examples should not be read as limiting the example in anyway. For example, different amounts of the components described in thefollowing examples as well as the components themselves can be changedaccording to the disclosure provided herein.

EXAMPLES Example 1 IV Acetaminophen Formulations

TABLE 1 Exemplary IV Formulation of Acetaminophen Acetaminophen 0.550g-1.000 g Excipients: Antioxidant  0.0100-0.0200 g pH modulator(s) qs pH5-6 Buffer  0.005-0.01 g Isotonic Agent  1.5-3.5 g Solvent  qs50.0-100.0 mL

Example 1A IV Acetaminophen Formulations

Example 1A is prepared according to the procedure outlined in Example 2using the amounts of the excipients described in Example 1.

Formula 1(A) Acetaminophen Excipients: 0.550 g 0.650 g 0.750 g 0.850 g0.950 g Antioxidant Reduced Reduced Reduced Reduced Reduced GlutathioneGlutathione Glutathione Glutathione Glutathione pH Modulator SodiumSodium Sodium Sodium Sodium hydroxide hydroxide hydroxide hydroxidehydroxide pH Modulator Hydrochloric Hydrochloric HydrochloricHydrochloric Hydrochloric Acid Acid Acid Acid Acid Buffering AgentSodium Sodium Sodium Sodium Sodium Citrate Citrate Citrate CitrateCitrate Isotonicity Agent Sodium Sodium Sodium Sodium Sodium ChlorideChloride Chloride Chloride Chloride Solvent Sterile Water Sterile WaterSterile Water Sterile Water Sterile Water for injection for injectionfor injection for injection for injection

Example 1B IV Acetaminophen Formulations

Example 1B is prepared according to the procedure outlined in Example 2using the amounts of the excipients described in Example 1.

Formula 1(B) Acetaminophen Excipients: 0.550 g 0.650 g 0.750 g 0.850 g0.950 g Antioxidant Methionine Methionine Methionine MethionineMethionine pH Modulator Sodium Sodium Sodium Sodium Sodium hydroxidehydroxide hydroxide hydroxide hydroxide pH Modulator HydrochloricHydrochloric Hydrochloric Hydrochloric Hydrochloric Acid Acid Acid AcidAcid Buffering Agent Sodium Sodium Sodium Sodium Sodium Acetate AcetateAcetate Acetate Acetate Isotonicity Agent Mannitol Mannitol MannitolMannitol Mannitol Solvent Sterile Water Sterile Water Sterile WaterSterile Water Sterile Water for injection for injection for injectionfor injection for injection

Example 1C IV Acetaminophen Formulations

Example 1C is prepared according to the procedure outlined in Example 2using the amounts of the excipients described in Example 1.

Formula 1(C) Acetaminophen Excipients: 0.550 g 0.650 g 0.750 g 0.850 g0.950 g Antioxidant Cysteine Cysteine Cysteine Cysteine CysteineHydrocloride Hydrocloride Hydrocloride Hydrocloride HydroclorideMonohydrate Monohydrate Monohydrate Monohydrate Monohydrate pH ModulatorSodium Sodium Sodium Sodium Sodium hydroxide hydroxide hydroxidehydroxide hydroxide pH Modulator Hydrochloric Hydrochloric HydrochloricHydrochloric Hydrochloric Acid Acid Acid Acid Acid Buffering AgentDisodium Disodium Disodium Disodium Disodium Phosphate PhosphatePhosphate Phosphate Phosphate Dehydrate Dehydrate Dehydrate DehydrateDehydrate Isotonicity Agent Mannitol Mannitol Mannitol Mannitol MannitolSolvent Sterile Water Sterile Water Sterile Water Sterile Water SterileWater for injection for injection for injection for injection forinjection

Example 1D IV Acetaminophen Formulations

Example 1D is prepared according to the procedure outlined in Example 2using the amounts of the excipients described in Example 1.

Formula 1(D) Acetaminophen Excipients: 0.550 g 0.650 g 0.750 g 0.850 g0.950 g Antioxidant Ascorbic Acid Ascorbic Acid Ascorbic Acid AscorbicAcid Ascorbic Acid pH Modulator Sodium Sodium Sodium Sodium Sodiumhydroxide hydroxide hydroxide hydroxide hydroxide pH ModulatorHydrochloric Hydrochloric Hydrochloric Hydrochloric Hydrochloric AcidAcid Acid Acid Acid Buffering Agent Sodium Sodium Sodium Sodium SodiumTartate Tartate Tartate Tartate Tartate Isotonicity Agent GlycerolGlycerol Glycerol Glycerol Glycerol Solvent Sterile Water Sterile WaterSterile Water Sterile Water Sterile Water for injection for injectionfor injection for injection for injection

Example 1E IV Acetaminophen Formulations

Example 1E is prepared according to the procedure outlined in Example 2using the amounts of the excipients described in Example 1.

Formula 1(E) Acetaminophen Excipients: 0.550 g 0.650 g 0.750 g 0.850 g0.950 g Antioxidant Acetylcysteine Acetylcysteine AcetylcysteineAcetylcysteine Acetylcysteine pH Modulator Sodium Sodium Sodium SodiumSodium hydroxide hydroxide hydroxide hydroxide hydroxide pH ModulatorHydrochloric Hydrochloric Hydrochloric Hydrochloric Hydrochloric AcidAcid Acid Acid Acid Buffering Agent Disodium Disodium Disodium DisodiumDisodium Phosphate Phosphate Phosphate Phosphate Phosphate DehydrateDehydrate Dehydrate Dehydrate Dehydrate Isotonicity Agent SorbitolSorbitol Sorbitol Sorbitol Sorbitol Solvent Sterile Water Sterile WaterSterile Water Sterile Water Sterile Water for injection for injectionfor injection for injection for injection

Example 1F IV Acetaminophen Formulations

Example 1F is prepared according to the procedure outlined in Example 2using the amounts of the excipients described in Example 1.

Formula 1(F) Acetaminophen Excipients: 0.550 g 0.650 g 0.750 g 0.850 g0.950 g Antioxidant metabisulfite metabisulfite metabisulfitemetabisulfite metabisulfite pH Modulator Sodium Sodium Sodium SodiumSodium hydroxide hydroxide hydroxide hydroxide hydroxide pH ModulatorHydrochloric Hydrochloric Hydrochloric Hydrochloric Hydrochloric AcidAcid Acid Acid Acid Buffering Agent Disodium Disodium Disodium DisodiumDisodium Phosphate Phosphate Phosphate Phosphate Phosphate DehydrateDehydrate Dehydrate Dehydrate Dehydrate Isotonicity Agent GlucoseGlucose Glucose Glucose Glucose Solvent Sterile Water Sterile WaterSterile Water Sterile Water Sterile Water for injection for injectionfor injection for injection for injection

Example 2 Preparation of IV Formulation Solutions

Prior to storage the formulations set forth in Example 1 are subjectedto bubbling with nitrogen, transferred to Type II colorless bottles, andthen placed under vacuum (low pressure approx. 550 mm of Hg) beforestoppering the bottles with a synthetic elastomer grey stopper crimpedwith an aluminum cap. The residual oxygen content is approximately 1.5ppm of dissolved oxygen. The bottles are then sterilized at 121° C. for15 minutes. Sterile solutions are stored at ambient temperature (lessthan 30° C.) for up to two years prior to use.

Example 3 A Phase III Randomized, Double-Blind, Placebo-Controlled,Multi-Center, Parallel-Group, Repeated-Dose Study of the AnalgesicEfficacy and Safety of 650 mg IV Acetaminophen Versus Placebo for theTreatment of Postoperative Pain After Abdominal Laparoscopic Surgery

In an effort to provide an intravenous, non-NSAID, non-opioid treatmentfor pain relief, the safety and efficacy of a 650 mg IV dose of APAP forthe treatment of acute pain is examined.

Study Design and Evaluation

A Phase III, randomized, double-blind, Placebo-controlled, multi-center,parallel-group, repeated dose study is conducted in approximately 240Subjects who have undergone planned or elective abdominal laparoscopicsurgery. Approximately 15 to 20 US sites will participate in the Study.

Subjects will be centrally randomized, across all study centers, toreceive infusions of Study Medication (either APAP or Placebo) at a doseat a dose (650 mg, 1000 mg, or placebo) and schedule described below.

Timed PI and pain relief (PR) Assessments will begin at baseline justprior to T0, the start of the first infusion of Study Medication, andcontinue through T24 hours.

All Subjects have access to rescue medication at all times throughoutthe study, as described below.

The Study will include the following assessment periods and procedures:

Screening (Day-21 to Randomization)

Screening is the period that begins when the Subject signs the InformedConsent Form and ends with randomization to Study Medication on POD1.During this period, the eligibility and baseline status of the Subjectare determined.

Treatment Period (Dose 1/T0/POD1 to T24/POD2)

Administration of Study Medication (and Study-related assessments) willoccur from T0 (morning of POD1) to T24 hours (morning of POD2).

Criteria for Evaluation

The primary efficacy endpoint is SPID24 (defined as the Sum of VAS scoredifferences from baseline at T0 to T24), excluding all data after rescuemedication.

Subject Selection Criteria

To be eligible for entry into the Study, Subjects must meet all of thefollowing criteria prior to surgery: (1) Provide written InformedConsent prior to participation in the Study; (2) is scheduled to undergoabdominal laparoscopic surgery (laparoscopic gastric bypass proceduresare not eligible); (3) If Subject is a female of childbearing potential,have a negative pregnancy test within 21 days of surgery; (4) be atleast 18, but not more than 80 years of age; (5) Have a Body Mass Index(BMI)≧19 and ≦45 lb/in²; (6) Have an ASA risk class of I, II, or IIIaccording to the American Society of Anesthesiologists; (7) Have theability to read and understand the Study procedures and the use of thepain scales and have the ability to communicate meaningfully with theStudy Investigator and staff; (8) Be free of other physical, mental, ormedical conditions which, in the opinion of the Investigator, makesStudy participation inadvisable

Exclusion Criteria (Screening)

A Subject is NOT eligible for entry if ANY of the following criteria aremet: (1) Used opioids or tramadol daily for greater than 7 days prior toStudy Medication administration (Subjects who, in the Investigator'sopinion have or are developing opioid tolerance are to be excluded); (2)Has been treated with Chapparal, Comfrey, Germander, Gin Bu Huan, Kava,Pennyroyal, Skullcap, St. John's Wort, or Valerian within 14 days priorto surgery; (3) Has significant medical disease(s), laboratoryabnormalities or condition(s) that in the Investigator's judgment couldcompromise the Subject's welfare, ability to communicate with the Studystaff, complete Study activities, or would otherwise contraindicateStudy participation; (4) Has known hypersensitivity to opioids,acetaminophen, or the inactive ingredients (excipients) of the StudyMedication; (5) Has known or suspected history of alcohol or drug abuseor dependence within the previous 2 years; (6) Has impaired liverfunction, e.g., AST/ALT/bilirubin greater than or equal to 3.0 times theupper limit of normal, active hepatic disease, evidence of clinicallysignificant liver disease, or other condition (e.g., alcoholism,cirrhosis, or hepatitis) that may suggest the potential for an increasedsusceptibility to hepatic toxicity with Study Medication exposure; (7)Has been treated with monoamine oxidase inhibitors (MAOIs) within 7 daysprior to surgery; (8) Has participated in another clinical Study(investigational or marketed product) within 30 days of surgery

Post Operative Exclusion Criteria

The Subject must not meet any of the following criteria after surgeryand prior to randomization to Study Medication: (1) Had any othersurgery than the planned laparoscopic surgery or had intra operative orpost operative complications which in the view of the Investigator wouldmake Study participation inadvisable; (2) Has taken non steroidalanti-inflammatory drugs (NSAIDs), steroids or MAOIs during the day aftersurgery. Exceptions: The use of low-dose aspirin, e.g., 81 mg/day, forcardioprophylaxis, and topical or inhaled steroids are acceptable; (3)Had any neuraxial opioids or continuous local anesthetic infusions viapercutaneous catheters administered as part of the anesthetic or postoperative analgesic management (local anesthetic infiltration ofsurgical wounds at the time of closure is acceptable if done as a singleinjection); (4) Had a fever (greater than 38.6° C. or 101.5° F.)requiring treatment.

Postoperative Assessment (POD0)

The Subject will undergo abdominal laparoscopic surgery or otherapproved surgical procedure as described herein. Details of the surgicalprocedure(s) will be recorded on the CRF including the type ofprocedure(s) performed and perioperative medication will be recorded.

Example 4 Phase III, Open-Label, Prospective, Multi-Center, RepeatedDose, Randomized, Multi-Day Safety and Efficacy Study of 650 mg IVAcetaminophen

A Phase III, open-label, prospective, multi-center, repeated dose,randomized, multi-day safety and efficacy study was conducted in 213subjects. The subjects were randomized as follows: 92 subjects to a q6group (1 g of IV acetaminophen every 6 hours), 91 subjects to a q4 group(650 mg of IV acetaminophen every 4 hours), and 28 subjects to astandard of care control group, which could include oral acetaminophen,but no IV acetaminophen. Subjects who completed 5 days of studytreatment included 63 in the q6 group, 59 in the q4 group and 26 in thecontrol group. The primary endpoint was an assessment of safety usingspontaneous adverse event reporting and daily liver enzymes. Efficacyevaluations were also performed.

Inclusion Criteria (Screening)

To be eligible for entry into the Study, Subjects had to meet all thefollowing criteria: (1) Provide written informed consent prior toparticipation in the Study; (2) Be at least 18 years of age and weigh atleast 41 kg; (3) Be anticipated by the Investigator to require multi-day(target is five days) use of IV treatment either because of: (a) havinga “nothing by mouth” (NPO) status, (b) having a medical condition thatmakes oral intake difficult, or (c) having a medical condition thatrequires IV treatment; (4) Be willing to undergo 5 days of treatmentwith IV acetaminophen for the treatment of pain or fever (defined as acore temperature ≧38° C.). Subjects had a slightly less than 15% chance(one in seven) of being assigned to the Control Group and receivingstandard of care treatment, but no IV APAP; (5) Have the ability to readand understand the Study procedures and have the ability to communicatemeaningfully with the Study Investigator and staff; and (6) If a femaleof child bearing potential, have a negative pregnancy test within 48hours of randomization.

Exclusion Criteria (Screening)

A Subject was not eligible for entry if any of the following criteriawere met: (1) Had a significant medical disease, laboratory abnormalityor condition that, in the Investigator's judgment, could compromise theSubject's welfare or would otherwise contraindicate Study participation;(2) Was expected to have difficulty in communicating with the Studystaff or completing Study requirements (including follow up visits); (3)Had known hypersensitivity to acetaminophen or the inactive ingredients(excipients) of IV acetaminophen or any contraindication to receivingacetaminophen; (4) Had impaired liver function, e.g., ALT greater thanor equal to 3 times the upper limit of normal (ULN), bilirubin greaterthan or equal to 3 times ULN, known active hepatic disease (e.g.,hepatitis), evidence of clinically significant chronic liver disease orother condition affecting the liver (e.g., alcoholism as defined byDSM-IV, cirrhosis or chronic hepatitis); or (5) Had participated in aninterventional clinical Study (investigational or marketed product)within 30 days of Study entry.

Efficacy Analysis

All analyses of efficacy were conducted on the modified intent-to-treatpopulation separately for the two indications (acute pain and fever).Subjects' Global Evaluations were summarized descriptively (n, mean, SD,median, minimum, and maximum) by treatment group for each study day andfor overall assessments. Summary statistics were also provided for eachsite.

Comparisons of efficacy endpoints between the following pairs oftreatment groups were investigated using two-sided tests at the 5% levelof significance:

IV acetaminophen 1 versus IV acetaminophen 650 mg

IV acetaminophen 1 g versus standard of care treatment

IV acetaminophen 650 mg versus standard of care treatment

A one-way analysis of variance (ANOVA) model with treatment group as thefactor was used to test the treatment difference between these pairs.All groups were included in this analysis model. The p-values from theANOVA model were presented along with the summary statistics.

Safety Analyses

All analyses of safety were conducted on the safety population.

Percentage of subjects withdrawn due to adverse event, percentage ofsubjects with adverse events (AEs) or serious adverse events (SAEs), andpercentage of subjects with clinically meaningful changes in laboratoryparameters were summarized.

All adverse events and serious adverse events were coded according tothe Medical Dictionary for Regulatory Activities (MedDRA), Version 10.0.Additional analyses included displays of the number of subjectsreporting at least one AE (incidence table), total number of episodes ofeach AE by body system and by severity, total number of episodes of eachAE by body system, and by attribution. Liver function test abnormalitieswere graded using the Common Terminology Criteria for Adverse Events.

For each clinical laboratory parameter, descriptive statistics (n, mean,standard deviation, median, and range) were tabulated for baseline andfinal values. Change from baseline was tabulated for those subjects whohad both baseline and final values. Liver function tests were alsoevaluated using values that were normalized to the upper limit of normalvalues for the local laboratory.

A shift table was prepared to present the shift in baseline clinicallaboratory values that were clinically relevantly high or low atbaseline and/or final measurement.

Descriptive statistics (n, mean, standard deviation, median, and range)were tabulated for changes in vital signs from baseline to finalmeasurement.

Results

Disposition of Subjects

A total of 257 subjects were screened for study enrollment. Of the totalscreened, 44 were screen failures, and 213 were enrolled and randomized:92 subjects in the q6 group, 91 subjects in the q4 group, and 28subjects in the control group. Subjects who completed 5 days of studytreatment included 63 in the q6 group, 59 in the q4 group and 26 in thecontrol group.

Subjects in the q4h group and q6h group were considered to be a StudyTreatment Discontinuation/Early Termination if they received at leastone dose of IV acetaminophen and discontinued study participation priorto completion of Day 5 treatments. Subjects in the control group wereconsidered to be a Study Treatment Discontinuation/Early Termination ifthey discontinued at any time after T0, but prior to completion of Day 5standard of care treatments.

Subjects who received at least one dose of IV acetaminophen anddiscontinued study participation prior to completing Day 5 treatments,but returned for the Last Study Visit were considered as “PartialTreatment Completers”. Similarly, subjects in the control group whodiscontinued study participation prior to completing Day 5 standard ofcare treatments, but returned for the Last Study Visit were consideredas “Partial Treatment Completers”.

Subjects who completed Day 5 treatments (IV acetaminophen or standard ofcare) and procedures were characterized as a “Treatment Completer”. ATreatment Completer who elected to discontinue study participation priorto the Last Study Visit was characterized as a Treatment Completer EarlyTermination.

Safety Outcome

There were no clinically relevant differences between the treatmentgroups in the frequency of serious, severe, related, or overalltreatment emergent adverse events (TEAEs). In fact, most TEAEs wereassessed by the Investigator to be mild or moderate in severity. Thefrequency of liver enzyme elevations seen in the treatment groups wascomparable. More specifically, with regard to the hepatic transaminasesalanine aminotransferase and aspartate aminotransferase, the frequencyand severity of the elevations were comparable between the treatmentgroups. There were no clinically relevant differences between thetreatment groups regarding laboratory assessments, vital signs, orphysical examinations. Thus, based on these data, intravenousacetaminophen in both active treatment groups (i.e., 650 mg and 1000 mgdose groups) was well tolerated.

Efficacy Outcome

The modified intent-to-treat population was used for all analyses ofefficacy: Subject Global Evaluations (rating of study treatments andrating of satisfaction with side effects related to study treatments)provided as a daily lookback (days 2 through 5) and overall evaluation(overall treatment period lookback) using a 4 point categorical ratingscale (0=poor, 1=fair, 2=good, 3=excellent). A one-way ANOVA model withtreatment group as the factor was used to test the treatment differencebetween each treatment pair:

IV acetaminophen 1 q6h versus IV acetaminophen 650 mg q4h

IV acetaminophen 1 g q6h versus standard of care treatment (Control)

IV acetaminophen 650 mg q4h versus standard of care treatment (Control)

All endpoints were tested at the 0.05 significance level (two-sided).

The IV acetaminophen 650 mg q4h group relative to the control groupproduced statistically significantly better satisfaction ratings for theSubject Global Assessments rating the level of satisfaction with theside effects related to study treatments the on the day 5 (mean rating2.4 vs. 2.0, p=0.0167) and at the end of day 5 prior to discharge (meanrating 2.4 vs. 2.0, p=0.0129) 24 h look back assessments. On day 4, thesatisfaction rating showed a trend to significance (mean rating 2.5 vs.2.2, p=0.1162). With respect to the Subject Global Assessments ratingthe level of satisfaction with the study treatments, there were nostatistically significant differences between the IV acetaminophen 650mg q6h group and control group at any of the assessment points. For theboth of the Subject Global Assessments rating either the level ofsatisfaction with the study treatments or the level of satisfaction withthe side effects related to study treatments, there was no statisticallysignificant differences between the two active treatment groups withrespect to the daily 24 h lookback assessments on day 2, day 3, day 4,day 5, or at the end of day 5 prior to discharge; nor was there astatistically significant difference on the overall assessment at theStudy Completion Visit.

The IV acetaminophen 1 g q6h group produced statistically significantlybetter satisfaction ratings for the Subject Global Assessments ratingthe level of satisfaction with the side effects related to studytreatments on day 5 (mean rating 2.4 vs. 2.0, p=0.0062) and at the endof day 5 prior to discharge (mean rating 2.5 vs. 2.0, p=0.0073) 24 hlookback assessments compared to the control group. On day 4, thesatisfaction rating showed a trend to significance (mean rating 2.5 vs.2.2, p=0.0744). With respect to the Subject Global Assessments ratingthe level of satisfaction with the study treatments, there were nostatistically significant differences between the IV acetaminophen 1 gq6h group and control group at any of the assessment points.

Statistically significant differences were observed for both activetreatment groups versus the control group in the Subject GlobalAssessments rating the level of Satisfaction with the side effectsrelated to study treatments on the day 5 and on the end of day 5 priorto discharge daily 24 h lookback assessments. Thus, these data suggestthat the IV acetaminophen 1 q6h and 650 mg q4h groups were efficaciousand provided comparable efficacy based upon the global satisfactionratings.

Many modifications, equivalents, and variations of the present inventionare possible in light of the above teachings, therefore, it is to beunderstood that within the scope of the appended claims, the inventionmay be practiced other than as specifically described.

1-55. (canceled)
 56. A method of treating pain in a human subjectweighing at least 50 kg comprising: co-administering to the subject atherapeutically effective amount of a first pharmaceutical compositioncomprising about 500 mg to about 750 mg of acetaminophen and atherapeutically effective amount a second pharmaceutical compositioncomprising an opioid analgesic; wherein the first pharmaceuticalcomposition is administered to the subject intravenously.
 57. The methodof claim 56 wherein the administration of the first pharmaceuticalcomposition to the subject is repeated at least once every four hoursfor a twenty-four hour period.
 58. The method of claim 56, whereinsubject is administered less than 4 grams of acetaminophen over atwenty-four hour period.
 59. The method of claim 58, wherein the firstpharmaceutical composition is administered to the subject at least sixtimes in a period of 24 hours.
 60. The method of claim 58, wherein thefirst pharmaceutical composition is administered to the subject at leastseven times in a period of 24 hours.
 61. The method of claim 56, whereinthe first pharmaceutical composition comprises about 600 mg to about 700mg of acetaminophen.
 62. The method of claim 56, wherein the firstpharmaceutical composition comprises about 650 mg of acetaminophen. 63.The method of claim 56, wherein the opioid analgesic is selected fromthe group consisting of allylprodine, alphamethylfentanyl, alfentanil,bezitramide, buprenorphine, butorphanol, carfentanyl, codeine,dextropropoxyphene, dextromoramide, dezocine, diacetylmorphine,dihydrocodeine, dipapanone, dismorphine, dihydrocodeine, etorphine,fentanyl, hydrocodone, hydromorphone, ketobemidone, lefetamine,levorphanol, levo-alphacetylmethadol, levomethorphan, meptazinol,methadone, morphine, nalbuphine, nicomorphine, ohmefentanyl, opium,oripavine, oxycodone, oxymorphone, methadone,phenethylphenylacetoxypiperidine (PEPAP), pentazocine, pethidine,phenazocine, piritamide, prodine, propoxyphene napsylate, remifentanil,sufentanil, tilidine, thebaine, tramadol, and tapentadol.
 64. The methodof claim 63, wherein the opioid analgesic is selected from the groupconsisting of codeine, dihydrocodeine, hydrocodone, morphine, oxycodone,pentazocine, and tramadol.
 65. The method of claim 63, wherein theopioid analgesic is morphine.
 66. The method of claim 56, wherein thesecond pharmaceutical composition is administered to the subject orally,intravenously, recitally, or parenterally.
 67. The method of claim 56,wherein the second pharmaceutical composition is administered as asingle dose or in multiple doses.
 68. The method of claim 56, whereinthe first and second pharmaceutical compositions are administeredsimultaneously.
 69. The method of claim 68, wherein the first and secondpharmaceutical compositions are administered as a combined intravenousdosage form.
 70. The method of claim 56, wherein the first and secondpharmaceutical compositions are administered sequentially.
 71. Themethod of claim 70, wherein the first pharmaceutical composition isadministered prior to the second pharmaceutical composition or whereinthe second pharmaceutical composition is administered prior to the firstpharmaceutical composition.
 72. The method of claim 70, wherein thetiming between the administration of the first and second pharmaceuticalcompositions is from about 1 minute to less than about 12 hours.
 73. Themethod of claim 70, wherein the timing between the administration of thefirst and second pharmaceutical compositions is from about 1 minute toless than about 6 hours.
 74. The method of claim 70, wherein the timingbetween the administration of the first and second pharmaceuticalcompositions is from about 1 minute to less than about 3 hours.
 75. Themethod of claim 70, wherein the timing between the administration of thefirst and second pharmaceutical compositions is from about 1 minute toless than about 1 hour.